So if in fact I wanted to make sure this was a number, I should have done something like either try and convert it to a number, which of course failed here, or put in a check to say where it is.

因此实际上如果我想确保,这是一个数字的话，我们的课程上的代码,在这里失败了，你或许应该在这里，放一个检查的东西。

麻省理工公开课 - 计算机科学及编程导论课程节选